When something is so funny that your rolling on the floor laughing or peeing your pants dont matter how old you are you can be 80 and peeing your pants or rolling on the floor laughing its gotta be filarious .

ROLLING ON THE FLOOR LAUGHING WHILE PISSING YOUR SELF . ONE DAY ME AND MY FRIENDS WERE TALKING AND I THOUGHT OF SUMTHING FUNNY AND I PEED MY PANTS THAT WAS FILARIOUS.

origin: truncation of the two words 'fucking' and hilarious'
used when there is minimum time, for maximum impact, as there are only 4 syllables instead of six.
definition: something that has greatly amused you, or continues to do so, would be described as 'f-ilarious'

1. The Office (UK series) is f-ilarious. The US version however, will not be.
2. It was f-ilarious when that drunken fool started ripping down the posters outside my room last night.
3. The world can be made much simpler by using truncated words such as f-hilarious

an incredulously great word intertwining the words f-ing and 'hilarious', utilized when something is so amazingly funny that you are enveloped in laughter and cannot find the strength within you to cease the laughing.